Eruptive Mass Loss in Massive StarsEruptive Mass Loss in Massive StarsNathan Smith Nathan Smith - University of Arizona - University of Arizona

OUTLINE

Intro: Mass Loss in Massive-Star EvolutionWinds vs. Eruptions: Mass/Metallicity dependence?

Lessons from Eta Carinae:1843 Eruption: Poster child for episodic mass loss events

Diversity of LBVs and Extragalactic Transients:

LBVs: Diversity of winds, eruptions, spectra.

Type IIn Supernovae and Circumstellar Gas: Pre-SN mass loss: Evidence for precursor LBV-like

eruptions.

Dust formation/survival in Type IIn SNe:Special circumstances: Dense CSM.

Intro: Mass Loss in Massive-Star EvolutionWinds vs. Eruptions: Mass/Metallicity dependence?

Lessons from Eta Carinae:1843 Eruption: Poster child for episodic mass loss events

Diversity of LBVs and Extragalactic Transients:

LBVs: Diversity of winds, eruptions, spectra.

Type IIn Supernovae and Circumstellar Gas: Pre-SN mass loss: Evidence for precursor LBV-like

eruptions.

Dust formation/survival in Type IIn SNe:Special circumstances: Dense CSM.

Single-star mass-loss(STELLAR WINDS and ERUPTIONS)

Binary-star mass-transfer(ROCHE LOBE OVERFLOW)

END FATES of MASSIVE STARS: What type of supernovafrom which type of star?

Type II-P II-L

IIb

Type Ib

Type Ic (GRB)

Mass loser

Mass gainer

Mass gainer

Heger et al.Woosley et al.Maeder & Meynet

Paczynski et al. 67; Podsiadlowski et al. 92Image courtesy M. Modjaz

Type IIn /Ibn

60 M

120 MLBV

WR

Mass loss and stellar evolution:

LBV winds/eruptions

SN Ib/cSN Ib/c

= L/4GMc

SUPER EDDINGTONCONTINUUM-DRIVENWINDS/OUTBURSTS

Smith & Owocki 2006Owocki et al. 2004Shaviv et al. 2001

SUPER EDDINGTONCONTINUUM-DRIVENWINDS/OUTBURSTS

Smith & Owocki 2006Owocki et al. 2004Shaviv et al. 2001

?

Theorists don’t know what makes LBVs erupt

??

120120

20 20

M/MM/M

t = 0t = 0 2.5-3 Myr2.5-3 Myr

WRWR

MS clumpedMS clumped

MS homogeneous

MS homogeneous

zero metallicity?zero metallicity?

(consequences of overestimated mass loss rates)

Evolutionary tracks for massive stars depend on adopted steady mass loss rates (e.g., Maeder & Meynet 1994, 2000, 2003; Heger et al. 2003).

Problem: more recent modeling of spectra of O stars winds find LOWER mass-loss rates than “standard” by factors of 3-10 or more. (Factor of >3; Bouret et al. 2005; Factor of >10; Fullerton et al. 2005).

Evolutionary tracks for massive stars depend on adopted steady mass loss rates (e.g., Maeder & Meynet 1994, 2000, 2003; Heger et al. 2003).

Problem: more recent modeling of spectra of O stars winds find LOWER mass-loss rates than “standard” by factors of 3-10 or more. (Factor of >3; Bouret et al. 2005; Factor of >10; Fullerton et al. 2005).

Why are O-star winds clumpy? See papers by Owocki & Rybicki and this morning’s talk by Sunqvist

Why are O-star winds clumpy? See papers by Owocki & Rybicki and this morning’s talk by Sunqvist

Smith & Owocki2006

Smith & Owocki2006

Single-Star Evolution

120120

20 20

M/MM/M

t = 0t = 0 2.5-3 Myr2.5-3 Myr

WRWR

MS clumpedMS clumped

MS homogeneous

MS homogeneous

LBVsLBVs

zero metallicity?zero metallicity?

Type IIn

Type Ib/c

Type IIn

Type Ib/c

Smith & Owocki2006

Smith & Owocki2006

(consequences of overestimated mass loss rates)

Single-Star Evolution

Evolutionary tracks for massive stars depend on adopted steady mass loss rates (e.g., Maeder & Meynet 1994, 2000, 2003; Heger et al. 2003).

Problem: more recent modeling of spectra of O stars winds find LOWER mass-loss rates than “standard” by factors of 3-10 or more. (Factor of >3; Bouret et al. 2005; Factor of >10; Fullerton et al. 2005).

Evolutionary tracks for massive stars depend on adopted steady mass loss rates (e.g., Maeder & Meynet 1994, 2000, 2003; Heger et al. 2003).

Problem: more recent modeling of spectra of O stars winds find LOWER mass-loss rates than “standard” by factors of 3-10 or more. (Factor of >3; Bouret et al. 2005; Factor of >10; Fullerton et al. 2005).

Ejected mass = 10-15 M

KE = 1049.6 - 1050 ergErad = 1049.7 erg

Ejected mass = 10-15 M

KE = 1049.6 - 1050 ergErad = 1049.7 erg

Eta Carinae’s1843 eruption:Eta Carinae’s1843 eruption:

Range of Ejecta Speed = 40 - 650 km/s

Follows a Hubble law

Range of Ejecta Speed = 40 - 650 km/s

Follows a Hubble law

2.122 m H2 1-0 S(1)1.644 m [Fe II]

Gemini South/Phoenix R=60,000

Smith (2006) ApJ, 644, 1151Smith (2006) ApJ, 644, 1151

KE/Erad ≈ 1KE/Erad ≈ 1 Wind or Explosion?Wind or Explosion?

DUST MASS

Md ~ 0.1-0.15 M in one event! (Smith et al.)

Up to Md ~ 0.4 M including previous events? (Gomez et al. 2011)

DUST MASS

Md ~ 0.1-0.15 M in one event! (Smith et al.)

Up to Md ~ 0.4 M including previous events? (Gomez et al. 2011)

Massive Dusty Molecular Shell

Smith & Ferland (2007, ApJ, 655, 911)Smith & Ferland (2007, ApJ, 655, 911)

CLOUDY models: survival of H2 requires a density of nH = 106.7-7 cm-3 in the outer shell, implying a total gas mass of 17-35 M.

CLOUDY models: survival of H2 requires a density of nH = 106.7-7 cm-3 in the outer shell, implying a total gas mass of 17-35 M.

Outer shellCool dust 140 K

Molecular hydrogenThin shell

Inner ShellWarm dust 200 K

[Fe II] emission, etc.Thick shellne=104 cm-3

Outer shellCool dust 140 K

Molecular hydrogenThin shell

Inner ShellWarm dust 200 K

[Fe II] emission, etc.Thick shellne=104 cm-3

Ammonia in the outer H2 shell of Eta Carinae (Smith et al. 2006, ApJL, 645, L41)

Ammonia in the outer H2 shell of Eta Carinae (Smith et al. 2006, ApJL, 645, L41)

Despite Eta Car being an extremely luminous hot star, several molecules have been detected:

Near-IR H2 lines – first detection of molecules (Smith & Davidson 2001; Smith 2002; Smith 2006)

NH3 (3,3) - Ammonia detected with ATCA (Smith et al. 2006)

CH, OH detected in UV absorption with STIS (Verner et al. 2006; Nielsen et al.; Gull et al.)

CO, 13CO, CN, HCO+, HCN, HNC, H13CN, N2H+ detected with APEX (Loinard et al. 2012; arXiv:1203.1559)

Eta Car is unique laboratory for rapid molecule and dust formation in N-rich ejecta around hot stars.

Will the Dust & Molecules survive the SN?

Despite Eta Car being an extremely luminous hot star, several molecules have been detected:

Near-IR H2 lines – first detection of molecules (Smith & Davidson 2001; Smith 2002; Smith 2006)

NH3 (3,3) - Ammonia detected with ATCA (Smith et al. 2006)

CH, OH detected in UV absorption with STIS (Verner et al. 2006; Nielsen et al.; Gull et al.)

CO, 13CO, CN, HCO+, HCN, HNC, H13CN, N2H+ detected with APEX (Loinard et al. 2012; arXiv:1203.1559)

Eta Car is unique laboratory for rapid molecule and dust formation in N-rich ejecta around hot stars.

Will the Dust & Molecules survive the SN?

Massive Dusty Molecular Shell

CHEMICAL ABUNDANCE CHANGES IN THE OUTER EJECTA

Smith & Morse 2004

HST/WFPC2 F502N [O III] F658N [N II]

HST/WFPC2 F502N [O III] F658N [N II]

LBV eruptions can trigger sudden changes in chemical abundances…LBV eruptions can trigger sudden changes in chemical abundances…

Multiple eruptions…Multiple eruptions…

[O III]H[O II]

N/O ≥ 20

N/O ≈ 1

N/O ≈ 0.1

Nitrogen enrichment gets weaker at larger radii.Nitrogen enrichment gets weaker at larger radii.

Eta Carinae had multiple previous eruptions.

Another generation of stars is still forming nearby…

Most massive stars live fast, die young, etc.This might actually matter in starburst regions, early universe, proto-GC’s …

Eta Carinae had multiple previous eruptions.

Another generation of stars is still forming nearby…

Most massive stars live fast, die young, etc.This might actually matter in starburst regions, early universe, proto-GC’s …

1600 AD shell:

From [Fe II] lines:

M = 0.1-0.2 M .M = 0.01 M/yr

KE = 1047 ergs

Mass and KE similar to 1890 outburst of Eta Car’s Little Homunculus.

1600 AD shell:

From [Fe II] lines:

M = 0.1-0.2 M .M = 0.01 M/yr

KE = 1047 ergs

Mass and KE similar to 1890 outburst of Eta Car’s Little Homunculus.

The historical light curveof P Cygni (de Groot 1983)

[Fe II] 1.644 um

NICFPSGinsburg, Smith, & Bally (in prep.)

[Fe II] 1.644 um

NICFPSGinsburg, Smith, & Bally (in prep.)

P Cygni:

the only other nebula from a Galactic giant LBV eruption that was actually observed.

P Cygni:

the only other nebula from a Galactic giant LBV eruption that was actually observed.

Smith & Hartigan2006, ApJ, 638, 1045 Smith & Hartigan2006, ApJ, 638, 1045

400 yr {

~1200 yr old

ERad = 2.51048 ergs

OBSERVED MASSES OF LBV NEBULAE

In LBV shells, mass of ~10 M is typical for L* > 106 L.

In LBV shells, mass of ~10 M is typical for L* > 106 L.

Smith & Owocki (2006)ApJ Letters, 645, L45Smith & Owocki (2006)ApJ Letters, 645, L45

Pistol Star (Figer+99) Eta Car

P Cygni

AG Car(S. White)

HD 168625

(Smith 2007)

Sher 25

(Brandner+97)

Mass-loss rates of 0.01-1 M/yr……beyond limitations of a line-driven wind (~10-4 M/yr * L6)

Requires continuum driving or hydrodynamic explosions. Both are insensitive to metallicity.

Observing Giant Eruptions of Massive StarsObserving Giant Eruptions of Massive StarsReview of giant eruption light curves and spectra

(see Smith et al. 2011, MNRAS, 415, 773)

Unpredictable, violent, and erratic variability

+

Smith, Vink, & de Koter (2004)Smith, Vink, & de Koter (2004)

. Sher 25

• Eta Car

~ 0.9

~ 0.5

Wolf-Rayet(WC, WN)

MS

• Pistol *

RSGs

WNH

Lower-LuminosityLBV-like

ERUPTIONS?

Lower-LuminosityLBV-like

ERUPTIONS?

. SN1987A

Luminous Blue Variables(a.k.a. Hubble-Sandage variables)H&S ’53

“giant eruptions”

. SN1987A

• Eta Car

M.S.

• Pistol *

RSG

Explosions / eruptions / winds

Surface instability? …or deep energy deposition?

Covering a wider range of initial Mass

Don’t have good observational constraints on brief and relatively faint eruptive events.

(so far, just tip of the iceberg…)

…PTF, Pan-STARRS, LSST

Explosions / eruptions / winds

Surface instability? …or deep energy deposition?

Covering a wider range of initial Mass

Don’t have good observational constraints on brief and relatively faint eruptive events.

(so far, just tip of the iceberg…)

…PTF, Pan-STARRS, LSSTAGB

?

Main Lesson: LBVs and related phenomena are more diverse than we thought

Broad spectrum of energy, luminosity, duration, spectral properties…

PNe

also: binary mergers, electron capture SNe, etc. also: binary mergers, electron capture SNe, etc.

Massive Star Eruptions Create Dense and Dusty Circumstellar Shells…

What happens when they explode as Supernovae?

Massive Star Eruptions Create Dense and Dusty Circumstellar Shells…

What happens when they explode as Supernovae?

Type IInSupernovae

(n = narrow H lines)

Efficient conversion of KE Light

CONSTRAINTS FROM SUPERNOVA PROGENITOR STARS CONSTRAINTS FROM SUPERNOVA PROGENITOR STARS

II-P IIn

IIbIIb

II-L

Smith et al. (2011)MNRAS, 412, 1522Smith et al. (2011)MNRAS, 412, 1522

Type IIn supernovae are seen over a range of metallicity, including low-Z dwarf galaxies.

PROPERTIES OF SN2006gy’s CSMPROPERTIES OF SN2006gy’s CSM

A Massive LBV-like Shell: Clues from Spectral EvolutionA Massive LBV-like Shell: Clues from Spectral Evolution

.Time evolution of narrow H(Smith et al. 2010, ApJ, 709, 856)

• Narrow absorption gets weaker... …running out of CSM?• Narrow absorption gets broader... …faster CSM at larger radii?

.Time evolution of narrow H(Smith et al. 2010, ApJ, 709, 856)

• Narrow absorption gets weaker... …running out of CSM?• Narrow absorption gets broader... …faster CSM at larger radii?

NarrowNarrow Int.Int. BroadBroad

PROPERTIES OF SN2006gy’s CSMPROPERTIES OF SN2006gy’s CSM

A Massive LBV-like Shell: Clues from Spectral EvolutionA Massive LBV-like Shell: Clues from Spectral Evolution

NarrowNarrow Int.Int. BroadBroad

Hubble Flow at 150-500 km/s

Suggests 1049 erg ejection~8 yr before SN (fall 1998)

Hubble Flow at 150-500 km/s

Suggests 1049 erg ejection~8 yr before SN (fall 1998)

.Time evolution of narrow H(Smith et al. 2010, ApJ, 709, 856)

• Narrow absorption gets weaker... …running out of CSM?• Narrow absorption gets broader... …faster CSM at larger radii?

.Time evolution of narrow H(Smith et al. 2010, ApJ, 709, 856)

• Narrow absorption gets weaker... …running out of CSM?• Narrow absorption gets broader... …faster CSM at larger radii?

IR/optical echo: Massive dust shell at R=0.5-1 light year (ejected 1500 yr before SN).

Requires at least 0.1 M of dust ( > 10 M total mass).

IR/optical echo: Massive dust shell at R=0.5-1 light year (ejected 1500 yr before SN).

Requires at least 0.1 M of dust ( > 10 M total mass).

PROPERTIES OF SN2006gy’s CSMPROPERTIES OF SN2006gy’s CSM

Smith et al. 2008, ApJ, 686, 485Smith et al. 2010, ApJ, 709, 856Miller et al. 2010, AJ, 139, 2218

Smith et al. 2008, ApJ, 686, 485Smith et al. 2010, ApJ, 709, 856Miller et al. 2010, AJ, 139, 2218

1-2 Years Later…IR Echo from dusty outer shell1-2 Years Later…IR Echo from dusty outer shell

KeckLGS/AOinfrared

visual

PROPERTIES OF SN2006gy’s CSMPROPERTIES OF SN2006gy’s CSM

1-2 Years Later…IR Echo from dusty outer shell1-2 Years Later…IR Echo from dusty outer shell

KeckLGS/AOinfrared

visual

Multiple massive shell ejections.Multiple massive shell ejections.

Dusty light echo:Outer massive shell, R ~ 1 lyejected ~1000-2000 yr earlier…another 10 M

Dusty light echo:Outer massive shell, R ~ 1 lyejected ~1000-2000 yr earlier…another 10 M

Inner massive shell, H-rich, 10-20 M, 100-600 km/s, Hubble lawInner massive shell, H-rich, 10-20 M, 100-600 km/s, Hubble law

SN2006jc

Foley et al. 200, ApJ, 657, L105Pastorello et al. 2007, Nature, 447, 829

Smith, Foley, & Filippenko 2008, ApJ, 680, 568

Foley et al. 200, ApJ, 657, L105Pastorello et al. 2007, Nature, 447, 829

Smith, Foley, & Filippenko 2008, ApJ, 680, 568

SN 2006jc had an observed precursoreruption 2 yr before exploding as a supernova…

SN 2006jc had an observed precursoreruption 2 yr before exploding as a supernova…

2 yr2 yr

Dust Formation Dust Formation

Explosion of WR star with dense CSM Explosion of WR star with dense CSM

Surprising Dust Formation in SN 2006jc

3 lines of evidence:

#1 Rapid fading

#2 Infrared emission from hot dust

#3 Far side blocked

Foley et al. (2007)Foley et al. (2007)

…faster than 56Co decay…faster than 56Co decay

Smith, Foley, & Filippenko 2008Smith, Foley, & Filippenko 2008

Surprising Dust Formation in SN 2006jc

3 lines of evidence:

#1 Rapid fading

#2 Infrared emission from hot dust

#3 Far side blocked

Day51

Day75

Day102

Day128

Smith et al. 2008Smith et al. 2008

Hot dust at ~1600 K.

Dust cools fast and piles up downstream. Total dust formed:

Md 0.01 M (Smith et al. 2008)

From later near/mid-IR obs:

Md 0.008 M (Matilla et al. 2008)

Smith, Foley, & Filippenko 2008Smith, Foley, & Filippenko 2008

Surprising Dust Formation in SN 2006jc

3 lines of evidence:

#1 Rapid fading

#2 Infrared emission from hot dust

#3 Far side blockedVel. (103 km/s)Vel. (103 km/s)

…but only seen in the narrow He I lines in the post-shock gas (swept-up CSM)…but only seen in the narrow He I lines in the post-shock gas (swept-up CSM)

Smith, Foley, & Filippenko 2008Smith, Foley, & Filippenko 2008

This is Wavelength-Dependent (stronger inblue em. lines)

CSM

He-rich

CSM

He-rich

SNejecta

C-rich?

SNejecta

C-rich?

Type IcSN

Type IcSN

SN2006jc.

Where did the dust form?

Blueshifted narrow He I lines: also from Zone 2

DUST FORMED IN THE SHOCK• Shocked CSM gas? (forward shock)• Shocked SN ejecta? (reverse shock)

Dust in/around Type IIn Supernovae

• IR Echoes from Pre-existing dust SN 2006gy ~0.1 M (Smith+08; Miller+10) SN2010jl 0.03-0.35 M ( Andrews+11)

several SNe IIn (Fox et al. 2009. 2011)

• Blueshifts suggest some new dust formation in post-shock gas as well.

SN 1995N (Fransson+02)SN 1998S (Pozzo+04;

molecules - Gerardy+00) SN 2005ip, 2006tf, 2008iy, 2010jl, others… (Smith+2008,2009,2012; Miller et al. 2010)

Dust in/around Type IIn Supernovae

• IR Echoes from Pre-existing dust SN 2006gy ~0.1 M (Smith+08; Miller+10) SN2010jl 0.03-0.35 M ( Andrews+11)

several SNe IIn (Fox et al. 2009. 2011)

• Blueshifts suggest some new dust formation in post-shock gas as well.

SN 1995N (Fransson+02)SN 1998S (Pozzo+04;

molecules - Gerardy+00) SN 2005ip, 2006tf, 2008iy, 2010jl, others… (Smith+2008,2009,2012; Miller et al. 2010)

dust formation in post-shock shell.dust formation in post-shock shell.

1.2 mm observations of z>6 quasars reveal huge amounts of dust. (Bertoldi et al. 2003, AA, 406, L55)

MD = few 108 M

Dust production of ~1 M/yr.

~0.01 M per SN…

1.2 mm observations of z>6 quasars reveal huge amounts of dust. (Bertoldi et al. 2003, AA, 406, L55)

MD = few 108 M

Dust production of ~1 M/yr.

~0.01 M per SN…

Massive star eruptions: Potential sources of dust in the early Universe?

Pre-SN Eruptions enable dust production in 2 ways:

1.Pre-existing dust seen as IR echoes.LOTS of dust – of order 0.01-0.2 M

2. New dust formation in post-shock gas when SN collides with dense CSM.

Radiative cooling and collapse of post-shock shell facilitates efficient dust formation.

Key questions:

1.Will that new dust survive?SNe IIn: slower shocks

no UV flash from shock breakoutdust already behind shock

2.Are there enough eruptive stars to do it?? … Early universe, low-Z, etc.

SUMMARY

Intro: Mass Loss in Massive-Star EvolutionEruptions: Dominate mass return, work at low-Z

Eruptions of LBVs - Eta Carinae et al.:Lots of mass return: CNO processed, dusty, molecule rich

Luminous Type IIn Supernovae and Circumstellar Gas: Pre-SN mass loss: Evidence for precursor LBV-like eruptions.

9% of all ccSNe: probably large fraction of very massive stars.

Dust formation/survival in Type IIn SNe:Special circumstances: Dense CSM, more dust than other

SNe.Qualitatively different from normal SNe: post-shock dust,

no (or weak) UV flash from shock breakout…

Intro: Mass Loss in Massive-Star EvolutionEruptions: Dominate mass return, work at low-Z

Eruptions of LBVs - Eta Carinae et al.:Lots of mass return: CNO processed, dusty, molecule rich

Luminous Type IIn Supernovae and Circumstellar Gas: Pre-SN mass loss: Evidence for precursor LBV-like eruptions.

9% of all ccSNe: probably large fraction of very massive stars.

Dust formation/survival in Type IIn SNe:Special circumstances: Dense CSM, more dust than other

SNe.Qualitatively different from normal SNe: post-shock dust,

no (or weak) UV flash from shock breakout…